Introduction

Transfer of large science data over wide area networks require maximum usage of the network throughput with a combination of transfer tools for high-speed/big file/ multiple file data movement. The complexity of data sources from multiple and distributed teams and complex science work-flow, scaling and spanning resources between multiple sites to store or process the data is becoming a challenge for hardware and software architecture.

To improve data transfer between different sites, dedicated computer systems and architectures are used to improve performance. Data Transfer Nodes (DTN) are used to overcome this problem. DTNs are dedicated (usually Linux based) servers, with specific hi-end hardware components and dedicated transfer tools and are configured specifically for wide area data transfer.

In science community many research groups employ a number of DTN instances, with dedicated network pipes for multiple high data file transfers, that bypass network firewalls, filtering services, BGP or QoS restrictions, etc. The challenge that research groups are facing is: “that despite the high performance of the hardware equipment, data transfers are much lower than the bandwidth provided (specialty with bandwidth beyond 40Gbit/s)”.

Why large scale data transfers matter for NRENs?

• It is a very common use case for the NRENs, supporting data-intensive science
• Short distance transfer
• Long distance transfer
• Very sensitive to packet loss
• Even a fraction of 1% packet loss leads to poor performance
• Congestion / provisioning
• Optimize network (Optimize network path, MTU, …)
• Deploy Science DMZ at the end sites / campuses - https://fasterdata.es.net/science-dmz/
• Other providers have the same concern, e.g., Google created an algorithm “Bottleneck Bandwidth and Round-trip time (BBR)”, which is far less sensitive to packet loss
• Established data-intensive transfer users (mainly the CERN community and WLCG) have already addressed this concern (File Transfer Service, and the same principles as Science DMZ).
• Long tail science, and emerging science disciplines, are subject to a poor experience